We are attempting to carry out a practical total synthesis of the tricyclic elemanolide dilactone, vernolepin. Vernolepin is a rare natural product which exhibits significant in vitro cytotoxicity and in vivo tumor inhibitory activity against Walker-256 rat carcinosarcoma. Our synthesis of vernolepin utilizes several new synthetic procedures developed in our laboratories for the efficient elaboration of the salient structural features of the natural product and substances related to it. The synthetic scheme is designed to allow a number of skeletal variations to be introduced into the basic vernolepin molecule. In addition, it permits isotopic labeling of vernolepin at a number of positions, an advantage which should be of value in biochemical studies. BIBLIOGRAPHIC REFERENCES: G.R. Kieczykowski, R.H. Schlessinger, and R.B. Sulsky, "Regiospecific Monoalkylation of 3-Butenenitrile," Tetrahedron Letters, 4647 (1975). J.L. Herrmann, G.R. Kieczykowski, S.E. Normandin, and R.H. Schlessinger, "A High Yield Stereospecific Total Synthesis of Eburnamonine and Eburnamine," Tetrahedron Letters, in press (1976).